1. Field
The present invention relates to wireless communications. More particularly, the present invention relates to a novel method and apparatus for providing multiple levels of quality of service in a wireless packet data network between a mobile station and a wireless network.
2. Background
The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA), frequency division multiple access (FDMA) and AM modulation schemes such as amplitude companded single sideband (ACSSB) are known in the art. These techniques have been standardized to facilitate interoperation between equipment manufactured by different companies. Code division multiple access communication systems have been standardized in the United States in Telecommunications Industry Association TIA/EIA/IS-95-B, entitled “MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL-MODE WIDEBAND SPREAD SPECTRUM CELLULAR SYSTEMS”, and referred to herein as IS-95. In addition, a new standard for CDMA communication systems has been proposed in the United States in Telecommunications Industry Association (TIA), entitled “Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems, Release A—Addendum 1”, dated Oct. 27, 2000, and referred to herein as “cdma2000.”
The International Telecommunications Union recently requested the submission of proposed methods for providing high rate data and high-quality speech services over wireless communication channels. A first of these proposals was issued by the Telecommunications Industry Association, entitled “The IS-2000 ITU-R RTT Candidate Submission.” A second of these proposals was issued by the European Telecommunications Standards Institute (ETSI), entitled “The ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT Candidate Submission”, also known as “wideband CDMA” and hereinafter referred to as “W-CDMA.” A third proposal was submitted by U.S. TG 8/1 entitled “The UWC-136 Candidate Submission”, hereinafter referred to as “EDGE.” The contents of these submissions is public record and is well known in the art.
IS-95 was originally optimized for transmission of variable-rate voice frames. Subsequent standards have built on the standard to support a variety of additional non-voice services including packet data services. One such set of packet data services was standardized in the United States in Telecommunications Industry Association TIA/EIA/IS-707-A, entitled “Data Service Options for Spread Spectrum Systems”, incorporated by reference herein, and hereafter referred to as “IS-707.”
IS-707 describes techniques used to provide support for sending Internet Protocol (IP) packets through an IS-95 wireless network. Packets are encapsulated into a featureless byte stream using a protocol called Point-to-Point Protocol (PPP). Using PPP, IP packets can be transported over a wireless network in segments of arbitrary size. The wireless network maintains PPP state information for the duration of the PPP session, or as long as additional bytes may be sent in the continuous byte stream between the PPP end points.
Such a continuous byte stream is subsequently encapsulated into a series of IS-95 frames using a protocol called Radio Link Protocol (RLP). RLP includes an error control protocol that uses negative acknowledgments (NAKs) by which the receiver prompts the sender to retransmit lost RLP frames. Because the RLP error control protocol uses retransmissions, RLP data transmission generally exhibits a variable transmission delay from sender to receiver. A modified form of RLP called Synchronous RLP (SRLP), in which no NAKs and no retransmissions are sent by sender or receiver, is well known in the art. The frame error rate in SRLP is greater than that of RLP, but the transmission delay is kept to a minimal constant.
A remote network node such as a personal or laptop computer (PC) connected to a packet-data-capable wireless mobile station (MS) may access the Internet through a wireless network in accordance with the IS-707 standard. Alternatively, the remote network node such as a web browser may be built-in to the MS, making the PC optional. An MS may be any of a number of types of devices including, but not limited to PC card, personal data assistant (PDA), external or internal modem, or wireless phone or terminal. The MS sends data through the wireless network, where it is processed by a packet data serving node (PDSN). The PPP state for a connection between an MS and the wireless network is typically maintained within the PDSN. The PDSN is connected to an IP network such as the Internet, and transports data between the wireless network and other entities and agents connected to the IP network. In this way, the MS can send and receive data to another entity on the IP network through the wireless data connection. The target entity on the IP network is also called a correspondent node. The interaction between a MS and the PDSN have been standardized in EIA/TIA/IS-835, entitled “Wireless IP Network Standard,” dated June, 2000, and referred to herein as “IS-835.” One skilled in the art will recognize that, in some networks, the PDSN is replaced with an Interworking Function (IWF).
In order to provide more complex wireless network services, there is an increasing desire and need to provide different types of services simultaneously through a single wireless device. Examples include simultaneous voice and packet data services. Examples also include multiple types of packet data services, such as simultaneous web browsing and video conferencing. At the same time, technological advances are increasing the bandwidth available through a single wireless channel between a wireless device and the wireless network.
However, modern networks are not yet capable of supporting simultaneous packet data services having substantially different grades of service. For example, delay sensitive applications like video conferencing and voice over IP are optimally sent without RLP retransmissions in order to reduce the magnitude and variability of packet delay through the network. On the other hand, applications such as FTP, e-mail, and web browsing are less delay-sensitive, so are optimally sent using RLP retransmissions. Current wireless standards adequately support a wireless application that requires any one of several grades of service, but not multiple applications in a single MS, where the applications require different grades of service. There is therefore a need in the art for a way of supporting multiple applications in a single MS, where the multiple applications use different grades of service.